Cryptology ePrint Archive: Report 2003/250

Breaking the Stream Cipher Whitenoise

Hongjun Wu

Abstract: Whitenoise is a stream cipher with specification given at http://eprint.iacr.org/2003/249. In this paper, we show that Whitenoise is extremely weak. It can be broken by solving about 80,000 linear equations. And only about 80,000 bytes keystream are needed in the attack.

Note: The details of solving the linear equations are added to this report. The attacks on the reduced versions of Whitenoise are implemented and illustrated in this revised report. The experiment results confirm that it is easy to break the Whitenoise cipher.